04/25/2012 01:00 EDT | Updated 06/25/2012 05:12 EDT

Newt Gingrich reportedly set to end presidential bid

Republican presidential candidate Newt Gingrich is reportedly set to end his presidential campaign next week after saying he expects Mitt Romney will be the Republican nominee.

CNN reported sources from Gingrich's campaign as saying Wednesday that the candidate will formally announce he is dropping out of the race and will express support for Romney at an event next Tuesday in Washington.

It comes after Gingrich, who was at one point Romney's main rival for the nomination during an at-times bitter primary fight, called on the party to unite behind the former Massachusetts governor.

"You have to at some point be honest about what's happening in the real world as opposed to what you would like to have happened," Gingrich told supporters at a suburban Charlotte, N.C., restaurant the morning after Romney swept primary contests in five states.

"Gov. Romney had a very good day yesterday. You have to give him some credit. He's worked for six years. He put together a big machine.

Gingrich rapidly saw his campaign's fortunes and successed fade from his pinnacle in January, when he stunned Romney's well-financed and heavily favoured campaign with a surprise victory in South Carolina.

Colourful, defiant, at times outlandish

The twice-divorced former Georgia congressman and speaker of the House of Representatives provided a colourful streak to an otherwise drab lineup of Republicans, often speaking off the cuff with unexpected ideas, including having schoolchildren work as part-time janitors in schools, as well as his widely mocked promise ahead of the Florida primary to build a permanent lunar base by the year 2020.

In one candidates' debate, when asked by CNN moderator John King whether he cared to comment on one of his former wives' claims he sought an open marriage, a defiant Gingrich garnered a standing ovation from the audience by replying: "No, but I will."

But whatever momentum Gingrich had from South Carolina was stopped cold by Romney in the Florida primary. Gingrich, who decried Romney's negative ad blitz, never recovered to remain competitive in major states, instead seeing staunch social conservative Rick Santorum usurping him as Romney's principal adversary in recent months.

Santorum suspended his campaign two weeks ago but has so far stopped short of endorsing Romney, who has gathered a massive delegate lead and fundraising advantage over his competitors.

Gingrich's expected departure will leave only firebrand Texas congressman Ron Paul in the Republican race. But Paul, who has a dedicated group of supporters, does not have enough delegates to seriously threaten Romney for the nomination.

Gingrich now campaigning as 'citizen'

While Gingrich said Wednesday he "obviously" felt he would be the better candidate, he conceded it was now clear that Republican voters didn't agree.

"I also think that it's very, very important that we be unified," he said. "No conservative anyplace in America should have any doubt about the importance of defeating Barack Obama."

Gingrich did not formally withdraw from the race but said he is now campaigning as a "citizen." He did not explain what he meant.

"We are going to stay very, very active and we are working out the details of our transition," he said. "But I am committed to this party. I am committed to defeating Obama. We will find ways to try to be helpful. But I think it's pretty clear that Gov. Romney is ultimately going to be the nominee."